package com.itheima;

import java.util.Comparator;
import java.util.TreeSet;

public class TreeSetDemo {
    public static void main(String[] args) {
        //集合只能存储引用类型
        TreeSet<Integer>set1 = new TreeSet<>();
        //添加元素(1->包装成Integer对象->自动装箱)
        set1.add(1);
        set1.add(5);
        set1.add(4);
        set1.add(3);
        set1.add(2);
        for (Integer integer : set1) {
            System.out.println(integer);//由小到大，自动升序
        }
        test1();
        test2();
        System.out.println(sum(1,2,3,4,5));
    }


    public static void test1() {
        TreeSet<Student> set = new TreeSet<>();

        set.add(new Student("zhangsan", 18));
        set.add(new Student("lisi", 19));
        set.add(new Student("wangwu", 20));
        set.add(new Student("zhaoliu", 21));
        set.add(new Student("qianqi", 22));
        for (Student student : set) {
            System.out.println(student.getName()+"---"+student.getAge());
        }
    }



    public static void test2() {
//        Comparator<Student>comparator = new Comparator<Student>() {
//            @Override
//            public int compare(Student o1, Student o2) {
//                //按学生的年龄正序排序（o1-o2）
//                //按学生的年龄倒序排序（o2-o1）
//                return o1.getAge()-o2.getAge();
//            }
//        };

        Comparator<Student>comparator = (o1, o2) -> o1.getAge()-o2.getAge();
        TreeSet<Student> set = new TreeSet<>(comparator);
        set.add(new Student("zhangsan", 18));
        set.add(new Student("lisi", 19));
        set.add(new Student("wangwu", 20));
        set.add(new Student("zhaoliu", 21));
        set.add(new Student("qianqi", 22));

        for (Student student : set) {
            System.out.println(student.getName()+"---"+student.getAge());
        }
    }
    public static int sum(int...a) {
        int total = 0;
        for(int i=0;i<a.length;i++) {
            total += a[i];
        }
        return total;
    }

}
